In the next few months the firm hopes to expand the service to search images across the entire Web.

The technology promises enhanced photo finding that would make it easier to find people on the Internet.

But privacy advocates are concerned that Polar Rose and similar facial-mapping search engines will violate people's rights and potentially aid criminals.

Lee Tien is an attorney at the Electronic Frontier Foundation, an Internet watchdog group that focuses on privacy and civil liberties.

"Photos [posted online] are effectively anonymous now," Tien said, unless they are labeled with some sort if identifying text. "But if Polar Rose works the way they say it will, that's all going to change."

Tien said that this kind of technology could aid stalkers in tracking down their victims, or it could allow employers, insurance companies, and the government to pry into people's lives more than some of us would like.